So far, in communication networks, performing an encrypted communication between two devices requires a prior knowledge of the two devices with regard to each other. In systems with only two devices, this can easily be achieved by directly establishing a secure channel and exchanging certificates assuring the identity of the devices. In communication networks with a high number of communication devices though, certificate authorities are used for providing certificates to the individual communication devices. Each device is authenticated by the certificate authority with regard to the other devices. For example the European patent EP 0 477 180 B1 shows such a communication system.
Moreover it is known to use key servers for directly providing traffic encryption keys to the devices. The devices then use these traffic encryption keys for encrypting traffic data, they wish to exchange.
It is though disadvantageous to use such a key server, since it has to be online at all times, so that a communication device can request a traffic encryption key at all times.
Accordingly, one object of the invention among others is to provide a communication device and a communication method, which allow for a secure communication of a plurality of communication devices within a communication network while requiring only minimal centralized always online hardware.